Float switch



Feb. 6, 1940. E. c. ALEXANDER 2,139,455

FLOAT SWITCH Filed Nov. 28, 1938 INVENTOR,

OFF fZ/As C. 44 EXA/VQFR.

A TTORNEYS.

Patented Feb. 6, 1940 "UNITED STATES FLOAT Elias 0. Alexander,

SWITCH San Francisco, Calif.

Application November 28, 1938, Serial No. 242,649

7 Claims.

My invention relates to improvements in float switches and it consists of the combinations, constructions, and arrangements hereinafter described and claimed.

This device relates to float switches, and has for its objective, to break electrical current when a liquid in a container reaches a predetermined level.

One of the devices many uses is to break a 1 current in a coffee maker of the type where the pressure in a lower heated liquid container forces the liquid into an uppercontainer.

When the liquid in the upper container reaches a predetermined level (and the application of heat is no longer necessary) the electrical heating element is automatically shut offend remains so until the switch is manually closed again.

The above effects are accomplished by means of the novel and efiicient construction as set forth.

It shall be noted that the figures in the drawing maybe so, modified in construction details to facilitate manufacturing the device, without departing from the spirit and scope of the i.n-'

vention.

Other objects and advantages will appear in the following specification, and the novel features of the device will be particularl pointed out in appended claims.

My invention is illustrated in the accompany ing drawing forming a part of this application,

in which Figure l is transverse section through the device, portions being shown in elevation; and

Figure 2 is a section along the line 2-2 of Figure l.

In carrying out my invention I made use of the upper receptacle of a coffee maker and show the upper portion of the receptacle at M in Figure l. The top of the eceptacle has an opening Ma for receiving the reduced portion is of a cylindrical. molded container 2. The container is preferably constructed from an insulating material and is closed by a cover lb.

A non-circular insulating rod 2 is slidably mounted in a non-circular opening in the base of the container and is supported against downward movement by a disc 8 secured to a reduced portion l?! of the rod by pin 8a. A float H has a threaded stud Ill screwed into a threaded bare provided in the lower end of the rod 2.

Within the container i, I mount a fixed contact 4 that has a base 4' to which an electric wire 53a is secured, the wire being received in an electric wire conduit [3. A movable contact 3 is secured to. a spring .arm 3 carried by the side wall of the container. A secondwire l3b leads from the spring arm 3 to the conduit l3. It will be noted that a forked member I5 extends from the movable contact 3 and has its bifurcated end received in an anual groove l2a formed in the top of the rod 2. A vertical movement of the rod 2' in an upward direction will lift the forked member causing the latter to raise the movable contact 3 above the fixed contact 4 and flex the spring support 3'.. l

I provide novel means for moving an insulating arm 5 between the contacts when they are initially separated by the rising float. Figure 2 shows the arm pivoted at 6 and movable from the on position, shown by the full lines, into the off position, shown by the broken lines, The side wall of the container 5 has a slot 5a through which the arm extends. 'The free end of the arm is shaped to act as a handle.

The arm 5 is 'yleldingly held in abutting position against the side of the'movable contact 3 by a biasing means consisting of a spring 1 connected at one end. to a screw 7 and'having its other end received in an opening a in the arm. The spring will immediately move the arm from the on to the off position as soon as the contacts are separated.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. 1

The coffee maker is placed on the electric heater, not shown, with the amount. of water in the lower compartment and the required amount of ground coffee in the upper compartment. The container l is now placed over the opening in the upper receptacle M and constitutes a cover therefor. The float M will be suspended within the receptacle and is spaced above the ground coffee. The switch within the container i is in series with the heatingeiement and the source of current, and the switch is closed by moving the arm to the right in Fig,- ure 2, i. e., into the on position.

The'electrical heating element will now heat the water in the lower receptacle and the pressure developed in this receptacle will cause the water to move upwardly into the upper receptable l4 and mix with the ground coffee. .When the desired amount of water is transferred from the lower receptacle to the upper one, float II will be raised by the water will carry with it the movable contact to a position where the arm 5 may move between the contacts 3 and 4. The spring 1 moves the arm as soon as the float moves the contact 3 above the contact 4 to the required extent. The separation of the contacts will open the circuit to .the heating element and therefore thewater in the bottom receptacle of the coffee maker cannot boil dry. The insulating member 5 also prevents any arcing of the current between the contacts 3 and 4 during their separating movement.

The float i i is maintained in its raised position and is prevented from moving downwardly because the arm 5 will remain between the two contacts and space the contact from the contact 4. The device therefore needs no watching of any kind by the operator after the current is initially connected to theheating element by the switch. The arm 5 must be manually moved into on.position before the circuit can again be closed. The adjustment of the float H with respect to the rod 2 willpermit the operator to l determine-at what height he wishes the liquid in the receptacle It to reach before the switch is automatically opened.

It is evident that this device is useful in.

places where attentionis not given to shutting off the electric current when the coffee making is completed, when the water rises from the lower.

to the upper container.

This device may be sold as an accessory for the many non-automatic coffee makers now in use.

I claim I i f a v1. In a float operated switch, a fixed contact, a movable contact cooperating therewith and operated by a float, an insulating strip held in abutment with said movable contact in the engagement position of the contacts, biasing means for causing said insulating strip to enter between and hold apart said contacts upon their initial separation by said float. i

2. In a float operated switch, a pair ofsonara ble contacts, a float for separating one contact from the other when the float is moved, an insulating strip, and means for moving the strip between the contacts when the latter are seperated from each other by the float.

3. In a float operated switch, a fixed contact, a movable contact cooperating therewith, a float for moving the movable contact away from the fixed contact when the float is lifted, by a fluid,

saidfloat aiding in moving the movable contact toward the fixed contact when the fluid level lowers, and aspring actuated insulating strip movablebetween the contacts upon their initial separation by said float, said strip being manually 'movable for again permitting the contacts to touch each other when the fluid level permits the float to freely lower.

4. In a float operated switch, a pair of contacts,

yielding means for holding them together, a float aiding in holding the contacts together when a fluid fails to lift the float, and separating the contacts when the fluid raises the float, an inv sulating strip, and biasing means for moving the strip between the contacts upon their initial separation by the float.

5. Afloat switch comprising a housing; arod slidably mounted in the bottom of the housing, a

float secured to the-rod, a fixed contact disposed within. the housing, a movable contact yieldingly held against the fixed contact, connections between. the' rod and movable contact for lifting the contact above the fixed contact when the float raises the rod, an insulating member abutting against theni'ovable contact, and biasing means iormoving the members between the 'contacts when the contacts are initially separated by the float. I 1

6-. A float switch comprising a housing, a float carrying a rod slidably mounted in the housing base, a fixed contact, a movable contact normallycontacting with the fixed contact, connections between the rod and the movable contact for lifting it above the fixed contact when the float lifts the rod, an insulating arm, and biasing means for. moving the. arm between the contacts when they are initially separated by the float. i

7. A float switch comprising a housing; a float carrying a rod sidably mounted in the housing a fixed contact. a movable contact normally contacting with the fixed contact, connections between the rod and the movable contact ior lifting it above the fixed contact when the float lifts the rod, an insulating arm, and biasing means for moving the arm between the contacts when they are initially separated by the float, said arm being manually movable to the contacts to again move together.

ELIAS C. ALEXANDER. 

